CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of Chinese Patent Application No.
01 1 30985.7 filed on 29/08/01, now Chinese Pat. No.
ZL 01 1 30985.7, PCT Patent Application No.
PCT/CN02/00405 filed on 06/06/2002.
FIELD OF TECHNOLOGY
[0002] The present invention relates to a fusion inhibitor, which can be used in the treatment
of HIV infection.
BACKGROUND OF THE INVENTION
1. HIV and AIDS epidemic
[0003] Infection with Human Immunodeficiency Virus (HIV), a pathogenic retrovirus, can cause
Acquired Immunodeficiency Syndrome (AIDS) (
Barre-Sinossi, F. et al., 1983, Science 220: 868-870). Although macrophage, neuron and other cells can be infected by HIV (
Maddon et al., 1986, Cell 47:333-48), the CD4+ lymphocytes are the major target cells for HIV (
Dalgleish, A. et al., 1984, Nature 312:767-8), because HIV has strong affinity to the CD4 molecules on the surfaces of CD4+ cells.
HIV infection in a human body destroys so many CD4+ lymphocytes that the body begins
to lose its immune function, therefore an AIDS patient is highly vulnerable to various
infections, neuronal dysfunction, tumors, and so on. Suffering from the symptoms,
the patients die eventually (
edited by Levy, J.A.: Acute HIV infection and susceptible cells, published in U.S.A,
2000, Page 63-78).
[0004] With its severe symptoms and high mortality rate, the epidemic contagion of AIDS
has become one of the leading causes of death that is threatening human health. So
far in the entire world, people infected by HIV have accumulated to a total of 57,900,000.
21,800,000 people have died from AIDS in the last decade. 5,300,000 people were found
to have newly contracted HIV within the year 2000. In China, HIV infection spreads
rapidly. Experts estimated that in 2000 the population of HIV positives has exceeded
800,000-1,000,000, which includes both adults and children (WHO Report 2000, UNAIDS
and WHO)
[0005] Currently at least two types of HIV have been identified: HIV-1 (
Gallo, R. et.al., 1984, Science 224:500-503) and HIV-2 (
Clavel, F.et al., 1986, Science 223:343-346). Each of them has high genetic heterogeneity. For HIV-1 alone, there are at least
11 different genotype (A-J and O subtypes) (
Jonassen, T.O. et al., 1997, Virol. 231:43-47). The E subtype of HIV-1 is distributed mainly in Central Africa, Thailand, India,
Vietnam, Kampuchea, Malaysia, Burma, China, and western hemisphere (WHO Report 1996).
The HIV subtypes found in China are mostly B, E, or C subtype (
Yu, E.S. et al., 1996, American J. Public Health 86(8 Pt1): 1116-22).
[0006] The reproduction cycle of HIV has several important steps. First, the envelope glycoprotein
gp120 attaches itself to the host cell membrane through its specific binding with
CD4 molecule located on the surface of T4 lymphocyte. With the assistance of chemokine
co-receptor, the viral envelope fuses with the host cellular membrane (
Berger, E.A., et al., 1999, Ann. Rev. Immunol., 17: 657-700). After the fusion process, the HIV virion packed in nucleocapsid enters into the
host cell with its capsid shucked off and viral nucleic acid exposed. The viral reverse
transcriptase catalyzed the transcription of HIV single-stranded RNA into single-stranded
DNA, which is then transformed to double-stranded DNA by the catalysis of cellular
polymerase. The double-stranded DNA can either exist freely in cytoplasm or be integrated
as provirus into host chromosome DNA by the catalysis of viral integrase, thus engendering
HIV latent infection (
Roe, T. et al., 1997, J. Virol. 71(2):1334-40). Provirus, which will not be excised from the host chromosome, is very stable and
reproduces itself with the replication of host chromosome. After the HIV mRNA is translated
into a large polyprotein, the viral proteases cut and process the polyprotein to form
mature viral structural proteins (
Xiang, Y. & Leis, J., 1997, J. Virol. 71(3): 2083-91). These structural proteins, together with HIV nucleic acids, are finally assembled
into new virus granules and released outside the cell by budding (
Kiss-Lazozlo, Hohn, T., 1996, Trends in Microbiology 4(12):480-5).
[0007] In summary, the critical stages of HIV replication are: 1) attachment and entry into
host cell through a fusion process; 2) reverse transcription and integration; 3) protein
translation and processing; 4) virus assembly and release.
2. The treatment for HIV infection
[0008] Although great efforts have been dedicated to effective remedial and preventive methods
for many years, there is no working vaccine or cure for AIDS yet.
[0009] An ideal vaccine should be
innocuous and capable of inducing neutralizing antibodies as well as persistent immune responses
in mucous membrane and blood (
Levy,J.A.and Levy,J.A., 1988, Trens Med Rev. 2:265-71). Many HIV vaccines currently developed in the world are still in the stages of animal
trials. Although vaccines against HIV membrane proteins gp160 and gp120 have already
moved into first, second, or third stages of clinical trials, the results of the trials
are disappointing. Many vaccines that are effective to prevent HIV infection in laboratory
animals are not effective in human (
McElrath, M.J. et al., 1996, Pro. Natl Acad Sci. USA 93:3972-77). The fact that scientists are making little progress in HIV vaccine research could
be attributed to the complexity and variability of HIV genetic materials (
Bloom, B. R., 1996, Science 272:1888-1900).
[0010] The drugs against AIDS approved in the world could be classified into two categories:
HIV reverse transcriptase inhibitors (
Charles, C. J., et al., 1996, JAMA 276:146) and HIV protease inhibitors (
Miles, S. A. et al., International AIDS Society USA 4(3):15). Both of them aim at later stages of HIV infection-transcription and assembly of
new viruses. The well-known "Cocktail Therapy" is a combination therapy using both
types of inhibitors (
Lafeuillade, A., et al., 1997, J. Infect. Dis. 175:1051-55)
[0011] Reverse transcriptase inhibitors, including AZT, ddI, ddC, 3TC, and d4T, etc, would
induce drug resistance, sooner or later, that means the viruses become less sensitive
to the drugs, and the effective inhibition concentration of the drugs rise by several-fold
or even ten-fold (
Vella, S. and Floridia, M., 1996, International AIDS Society USA 4 (3):15). This drug-resistance is associated with high mutation rate of HIV In a human body,
a single HIV virus could produce 10
8-10
10 new virus granules every day, while the mutation rate is 3X10
5 per replication cycle. Many mis-sense mutations, affecting the expression of amino
acids, may happen in the regulatory genes as well as in the envelope proteins. In
some HIV strains, the mutation rate could be as high as 40% in the amino acid sequences
of certain genes(
Myers,G and Montaner,J.G.. 1992, The Retroviridae vol. 1, Plenum Press, New York 51-105). As a result, reverse transcriptase inhibitors lead to drug-resistance by facilitating
the proliferation of resistant strains that exist before and after the mutations in
addition to control sensitive virus strains.
[0012] Moreover, all the reverse transcriptase inhibitors have specific toxicity related
to their dosage. The symptoms include spinal cord suppression, vomiting, liver dysfunction,
muscle weakness, diseases of peripheral nervous system, and pancreatic inflammation.
Many patients have to suspend the treatment due to these intolerable side effects
(
Fischl, M.A., et al., 1987, N. Engl. J. Med 317:185-91;
Lenderking, W.R., et al., 1994, N. Engl. J. Med. 330:738-43).
[0013] Drug-resistance is also a major problem for protease inhibitors. Mutations in viral
protease gene have caused drug-resistance in all the protease inhibitors presently
used in AIDS treatment (
Condra, J. H. et al., 1995, Nature 374:569-71). The side effects of protease inhibitors include liver dysfunction, gastrointestinal
discomfort, kidney stone, numbness around mouth, abnormality of lipid metabolism,
and mental disorder (
Deeks, et al., 1997, JAMA 277:145-53).
[0014] In summary, most of the currently used anti-HIV drugs are highly toxic, and induce
drug-resistance. Therefore, there is still a huge obstacle in the treatment of HIV
infection. Apparently, it is urgent for the need of new drugs with better efficacy
and lower toxicity for the treatment of HIV infection.
[0015] New drugs can be developed against new targets in different stages of HIV replication
cycle. Recently a few of anti-AIDS drugs with new mechanisms have been developed after
in-depth research in HIV and AIDS. These drugs include some new HIV reverse transcriptase
inhibitors and HIV protease inhibitors, as well as some new anti-HIV agents aimed
at other targets that are listed here (
De, C. E., 2000, Rev. Med. Virol. 10 (4):255-77):
1). Virus absorbents, such as sodium lauryl sulfate, dextrose sulfate, and heparin,
can interrupt the cohesion of gp 120 on HIV envelope and the lymphocyte through the
action of polyanion groups. However, these absorbents have bad specificity and high
toxicity. Some of them can even increase the virus load (Baba, M., et al., 1988, Pro. Natl. Acad Sci. USA. 85:6132-6);
2). Soluble CD4s are used to prevent gp120 from binding to host cells. Some recombinant
soluble CD4s could bind the virus granules before gp120 contact the CD4 molecules
on cellular membrane and prevent HIV infection. However, these recombinant soluble
CD4s are of no apparent effect on the HIV-1 strains isolated from some patients. Moreover,
the clinical experiments did not provide any reliable evidence for their antiviral
activity (Gomatos, P. J. et al., 1990. J. Immunol. 144:4183-8);
3). Chemokines and their analogs, including RANTES, MIP-1α, MIP-1β binding with CCR5
and SDF binding with CXCR4, can be used to prevent HIV from entering into host cells.
They could not only competitively block the gomphosis between HIV gp120 and cellular
chemokine co-receptors but also limit HIV inbreak points by depressing the expression
of this co-receptor on cell. The latest chemokine co-receptor blockers include positive
charged small peptides such as ALX40-4C and T22, and compounds such as AMD3100, TAK-779
and trichosanthin.
4). Although soluble CD4-IgG can suppress HIV replication in vitro, it has no reliable
antiviral activity in clinical trials.
5). Agents such as 2,2'-dithiobisbenzamides (DIBAs) and azadicarbonamide (ADA) can
block the assembly and disassembly of viruses through interactions with NCp7 zinc
finger site.
6). A segment of gp41 or its analog can be used as a fusion inhibitor. For example,
T-20 is capable of blocking virus entry into the cell (Jiang, S. et al., 1993, Nature 365:113.)
7). Inhibitors of viral mRNA transcriptase, such as CGP64222, fluoroquinolone K-12,
and EM2487;
8. Inhibitors of integrase, such as derivatives of Carbonyl J [N,N'-bis(2-(5-hydroxy-7-naphthalenesulfonic
acid)urea], can prevent HIV from integrating its genome into host lymphocyte genome
(Maurer K, et al:, 2000, Bioorg Chem 28(3):140-155).
3. Fusion inhibitors blocking viral entry into cells
[0016] Many biological processes involve membrane fusion. In eukaryotic cells, the fusions
of cellular membranes are happening continuously, including endocytosis, secretion,
recycle of membranous components, and so on (
White, J.M., 1992, Science 258:917-24). Examples of fusion in some peculiar cells include the secretion of regulated fusion
hormone, enzyme, and nerve transmitter. Some more notable examples include the fusion
of germ cells and of muscle cells.
[0017] According to an embodiment of the present invention, the anti-fusion or anti-membrane
fusion drug is an agent that inhibits or suppresses the fusion of two or more biological
membranes. According to an embodiment of the present invention, two or more biological
membranes are either cellular or viral structures, such as cellular membrane and viral
envelope. According to an embodiment of the present invention, the antiviral agent
is a compound that inhibits viral infection of cells, such as the inhibition of virus
-cell fusion, or cell-cell fusion. According to an embodiment of the present invention,
the infection is related to membrane fusion, such as envelope viral infection of cells,
and other processes similar to viral and cellular fusion, such as what happens during
bacterial conjugation.
[0018] In conclusion, membrane fusion is a critical step for envelope virus to attack and
penetrate the host cells (
Weissenborn, W., et al., 1997, Nature 387:426-30). The anti-HIV drug of the present invention, Fusonex, as defined in claim 1 is a
fusion blocker to prevent viruses from entering host cells.
[0019] The fusion process is controlled by the glycoproteins on HIV envelope. The precursor
of the glycoproteins is gp 160 that has polysaccharide groups. During the virus reproduction
period, gp 160 is hydrolyzed by certain protease into two subunits: gp120, which is
outside the envelope, and gp41, which is a trans-membrane protein. After the hydrolyzation,
gp120 and gp41 are still linked by non-covalent bonds and polymerized as trimers outside
the virus granule. The trans-membrane protein gp41, whose ectodomain with a highly
helical structure, has a highly efficient origination mechanism for membrane fusion,
and is known as the pivotal molecule to open the gate of cells for its direct participation
in the fusing process of cellular membranes (
Ferrer, M., et al., 1999, Nat. Struct. Biol. 6(10):953-60;
Zhou, G., et al., 2000, 1: Bioorg. Med. Chem. 8(9)-2219-27).
[0020] It has been demonstrated by crystal diffraction analysis that when fusion takes place
between viruses and cells, the core of gp41 is composed of six helical bundles wherein
the N-terminal and C-terminal helices are collocated as three hairpins which fix the
HIV envelope to the cellular membrane. While the gp41 trimer can form a fusion pore
that facilitates the viral intrusion into the host cell (
Chan, D. C., et al., 1997, Cell 89:263-73), it exists in an unstable natural non-fusion-conformation on the surface of the
free virus granule fresh sprouting from infected cells. At first, the N-terminal helix
is wrapped inside the C-terminal helix so that the N-terminal fusion area is hidden,
then after gp120 on viral surface combines with the CD4 receptor and chemokine co-receptor
on the cellular membrane, an receptor-activated conformational change of gp41 occurs
in which its N-terminal extends beyond the viral surface into the host cellular membrane.
At this time, gp41 is transformed from an unstable natural non-fusion conformation
into a pro-hairpin intermediate conformation. When the C-terminal and N-peptides of
gp41 bind together, the hydrophobic N-terminal core of the trimer structure is exposed,
and the pro-hairpin intermediate is transformed into a more energy-stabilized hairpin
conformation, and by this time the viral envelope has fused with the cellular membrane
(
Jones, P. L., et al., 1998, J. Biol. Chem. 273:404).
[0021] The first fusion inhibitor ever discovered is a 36 amino-acid peptide derived from
the C-terminal (127——162) of gp41——T-20, its sequence is as follows:
X-YTSLIHSLIEESQNQQEKNEQELLELDKWASLWNWF-Z.
[0022] The structural similarity of T-20 to the C-terminal of gp41 makes it capable of competing
with the C-peptide of gp41 in binding with its N-terminal fusion area. On the surface
of T-cell, T-20 at very low concentration can interrupt the fusion between HIV gp41
and host cellular membrane (the IC
50 is within the range of nM) (
Jiang, S., et al. , 1993, Nature 365:113 ;
Wild, C. T. et al., 1994, Pro. Natl. Acad. Sci. USA 91:9770-74). In the pro-hairpin state which lasts many minutes, T-20 is very effective in inhibiting
the binding of the C-peptide of gp41 with its N-terminal fusion area, thus blocking
the formation of a hairpin between the viral envelope and cellular membrane (
Kliger, Y and Shai, Y., 2000, J. Mol. Biol. 295:163-8) .
[0023] Because a fusion inhibitor acts on the cellular membrane, it doesn't need to be released
inside cells to exert its function. In comparison, the anti-HIV drugs, currently in
clinical use, all act in the middle or late stages of viral infection of host cells,
that means they must be first released into the cells to be able to inhibit the reproduction
of the invading HIV. In addition, the highly conserved amino acid sequence of the
hydrophobic core of gp41 suggests that the virus is not likely to develop drug resistance
against the fusion inhibitors. It is shown in vitro experiments that T-20 can specifically
block HIV entry into cells. On the other hand, both the first and the second stages
of clinical trials have indicated that AIDS patients can put up well with T-20 administration.
T-20 has no toxicity against the spinal cord, and the most side effects are in low
grade, or in middle grade. In a daily dosage of 200mg, T-20 can remarkably reduce
the HIV loads in most patients, and 30% has fallen below a detectable level (lower
than 400/ml). Besides, T-20 is also effective to HIV patients who have already developed
drug resistance. It is reported that the number of CD4+ cells in some patients has
undergone some increase after the use of T-20 (
Kilby, J. M. et al., 1998, Nat. Med. 4:1302-1307). It has been worried that long term administration of T-20 might induce the production
of specific antibodies against T-20, that could cause the AIDS patients resistance
to T-20. Nevertheless, during an experiment of a few weeks, T-20 maintained antiviral
activity all the time (
Pilcher, C. D. et al., 1999, AIDS 13(15):2171-4)
.
[0024] Compared with the HIV reverse transcriptase inhibitors and protease inhibitors currently
in clinical use, the advantages of the fusion inhibitor T-20 are better efficacy,
lower toxicity, and no drug resistance yet. However, the clinical dosage of T-20 is
as high as 200mg per day is an indication of its bad stability and low anti-fusion
valence. In addition, because of such high dosage, T-20 has caused some local responses
in some patients (
Kilby, J. M. et al., 1998, Nat. Med. 4:1302-1307).
SUMMARY OF THE INVENTION
[0025] The present invention provides fusion inhibitors as defined in claim 1, with both
high stability and high valence for the treatment of HIV infection. The fusion inhibitors
of the present invention can be used in combination therapies against AIDS, in production
methods, or in other applications. In comparison with T20, the inhibitors of the present
invention have higher efficacy, and lower administration dosage, and thereby lower
toxicity
[0026] According to an embodiment of the present invention, the fusion inhibitor is a specific
peptide of 36 amino acid residues, with terminal-capping groups added to both ends
of the peptide.
[0027] The present invention provides the following technology schemes:
[0028] According to a preferred embodiment of the present invention, the fusion inhibitor
is a peptide derived from HIV trans-membrane glycoprotein gp41. According to a further
preferred embodiment of the present invention, the peptide has an amino acid sequence
as set forth in SEQ ID NO.: 1, and is set forth as follows:
X-SWETWEREIENYTKQIYKILEESQEQQDRNEKDLLE-Z (SEQ ID NO.: 1).
[0029] In the peptide (it is also called Fusonex in the following description),
X is an amino group or -X1-X2, wherein X1 is an imino group, and X2 is an acetyl group,
a hydrophobic group, or a macromolecule vector group; the hydrophobic group is preferably
an acarbobenzoxy group, a dansyl group, a tert-butyloxycarbonyl group, or a 9-fluorenylmethyloxycarbonyl
group; the macromolecule vector group is a lipid-fatty acid chelate, a polyethylene
glycol, or a carbohydrate;
Z is a carboxyl group or -Z1-Z2, wherein Z1 is a carbonyl group, and Z2 is an amino
group, a tert-butyloxycarbonyl group, a hydrophobic group, or a macromolecule vector
group.
[0030] As used herein, the single-letter codes representing amino acid residues are defined
as follows:
- A
- Alanine
- R
- Arginine
- N
- Asparagines
- D
- Aspartic acid
- C
- Cysteine
- Q
- Glutamine
- E
- Glutamic acid
- G
- Glycine
- H
- Histidine
- I
- Isoleucine
- L
- Leucine
- K
- Lysine
- M
- Methionine
- F
- Phenylalanine
- P
- Proline
- S
- Serine
- T
- Threonine
- W
- Tryptophan
- Y
- Tyrosine
- V
- Valine
[0031] According to a prepared embodiment of the present invention, X2 or Z2 or both are
hydrophobic group. The hydrophobic group is an acarbobenzoxy group, a dansyl group,
a tert-butyloxycarbonyl group, or a 9-fluorenylmethyloxycarbonyl group.
[0032] According to an alternative embodiment of the present invention, X2 or Z2 or both
are macromolecule vector group. The macromolecule vector group is a lipid-fatty acid
chelate, a polyethylene glycol or a carbohydrate.
[0033] In a further preferred embodiment of the present invention, the above-mentioned X2
is an acetyl group, and Z2 is an amino group.
[0034] According to an embodiment of the present invention, a composition for combination
therapy against AIDS comprises the inhibitor, and at least one component selected
from the group consisting of reverse transcriptase inhibitors, virus protease inhibitors,
glycosidase inhibitors, viral mRNA capping inhibitors, amphotericin B, ester bond
binding molecules castanospermine with anti-HIV activity, hydroxyurea, α-interferon,
β-interferon, and γ-interferon.
[0035] According to a preferred embodiment of the present invention, the reverse transcriptase
inhibitor is at least one selected from the group consisting of AZT (3' azide-2'.
3'-dideoxycytidine), ddI (2', 3'-dideoxyinosine), ddC (2', 3' -dideoxycytidine), ddA
(2', 3'-dideoxyadenosine), d4T (2', 3'-dideoxy-dideoxythymidine), 3TC, Nevirapine,
Atevirapine; Delavirdine, PMEA, PMPA, and/or loviride; the glycosidase inhibitor is
SC—48334 or MDL—28574 or both; the viral mRNA capping inhibitor is ribovirin.
[0036] The present invention also provides the inhibitor to be administered for the treatment
of HIV infection via injection, in oral dosage formulation, in rectal dosage formulation,
or in percutaneous dosage formulation;
[0037] A composition containing the inhibitor can also be administered for the treatment
of HIV infection via injection, in oral dosage formulation, in rectal dosage formulation,
or in percutaneous dosage formulation.
[0038] The inhibitor can be manufactured by applying common techniques and methods known
in the field. For instance, small peptides can be synthesized on a certain vector
or in a solution. Longer peptides can be produced by recombinant DNA technology, or
can be synthesized as several distinct segments and then connected together. The nucleotide
sequence encoding the peptide can be synthesized and/or cloned and expressed through
the technology familiar to an ordinary technician in this field.
[0039] This peptide can also be synthesized by putting other chemical groups to its amino
and/or carboxyl terminal to enhance its stability, bioavailability, and/or inhibitory
activity, etc. For example, hydrophobic groups, such as carbobenzoxy, dansyl, or tert-butyloxycarbonyl
group, can be added to the amino terminal, and acetyl or 9-fluorenylmethyloxycarbonyl
can also be placed at the amino terminal. The above-mentioned hydrophobic group, tert-butyloxycarbonyl
group, or amino group can be added to the carboxyl terminal of the peptide. In addition,
the peptide can be synthesized by changing its spatial conformation.
[0040] Furthermore, any of the above-mentioned peptides can have a non-peptide macromolecular
vector group linked to their amino and/or carboxyl terminal through a covalent bond,
including a lipid-fatty acid chelate, a polyethylene glycol, or a carbohydrate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041]
Figure 1 shows the amino acid sequence of Fusonex (SEQ ID NO.: 1), which is a polypeptide
composed of 36 amino acids. Fusonex is derived from the amino acid sequence (117-151)
(SEQ ID NO.: 2) at the C-peptide of HIV-1 gp41 (E subtype). In all the figures, the
above-mentioned single-letter codes are used for amino acids.
Figure 2 is the elution profile showing the characteristic peaks of Fusonex and the
complex of Fusonex and gp41 N-peptide (35-70) from Superdex chromatography column.
Figure 3 is the circular dichroism spectra of the macromolecular secondary structure
of the complex of Fusonex and gp41 N-peptide (35-70).
Figure 4 shows the stability comparison between Fusonex and T-20, wherein the curve
on the right side (solid circle) is the melting curve of Fusonex complexed with gp41
N-peptide, and the curve on the left side (hollow circle) is the melting curve of
T-20 complexed with gp41 N-peptide. It had been shown that, in the range of 35-80°C,
Fusonex is more stable than T-20 at the same temperature.
Figure 5 shows the fusion inhibitory activities of Fusonex and T-20. In this experiment,
the activity of luciferase was used for quantitative analysis of the fusion inhibitory
activities of Fusonex (circle) and T-20 (square). The cellular fusion was induced
by HIV-1 gp160HXB. When the effector cell expressing gp160HXB gene and T7 polymerase gene fuses with the target cell expressing CD4 gene and luciferase
reporter gene, the luciferase gene is expressed and a chemical fluorescence is radiated.
This experiment defines as 100% the luciferase activity of the control group in the
absence of any fusion inhibitor. It had been shown that, at the same concentration,
Fusonex has a better inhibiting activity than T-20, based on the comparison of their
inhibition activities of the cell fusion induced by HIV-1 gp160HXB.
DETAILED DESCRIPTION OF THE INVENTION
[0042] Based on the analysis of the three-dimensional structure of gp41, the present invention
provides a novel fusion inhibitor Fusonex. Detailed descriptions of the antiviral
peptide involved in the present invention are listed as follows:
- 1. Fusonex is a polypeptide composed of 36 amino acid residues. Fusonex (SEQ ID NO.:
1) is derived from the segment (the amino acid sequence from No. 117 to No.151) (SEQ
ID NO.: 2) of the C peptide of the ectodomain of HIV-1 (Subtype E) trans-membrane
protein gp41, its amino acid sequence of this segment is as follows:
WIEWEREI SNYTNQIYEILTESQNQQDRNEKDLLE (SEQ ID NO.: 2)
- 2. Add S (serine) to the N-terminal, because serine is generally added to the N-terminal
of a α-helix to increase its stability.
- 3. Substitute E (Glutamic acid) for 1 (Isoleucine) at No. 118, so that it forms a
charge-charge interaction with R (Arginine) at No.122, which can increase the stability
of the α-helix.
- 4. Substitute T (Threonine) for E (Glutamic acid) at No.119, the intention is to cover
the hydrophobic pocket including W (Tryptophan) 117, W120 and W60.
- 5. Substitute E (Glutamic acid) for S (Serine) at No. 125, so that it can form a charge-charge
interaction with K (Lysine) at No. 129, which can increase the stability of the α-helix.
- 6. Substitute K (Lysine) for N (Asparagines) at No. 129, so that it can form a charge-charge
interaction with E (Glutamic acid) at No. 125, it can increase the stability of the
α-helix.
- 7. Substitute K (Lysine) for E (Glutamic acid) at No.133, so that it can form a charge-charge
interaction with E (Glutamic acid) at No. 136 and No.137, it can increase the stability
of the α-helix.
- 8. Substitute E (Glutamic acid) for T (Threonine) at No. 136, so that it can form
a charge-charge interaction with K (Lysine) at No. 133, it can increase the stability
of the α-helix.
- 9. Substitute E (Glutamic acid) for N (Asparagines) at No. 140, so that it can form
a charge-charge interaction with R (Arginine) at No. 144, it can increase the stability
of the α-helix.
[0043] After a series of the above-mentioned alterations, the new viral fusion inhibitor
Fusonex is composed of the following amino acid sequence:
SWETWEREIENYTKQIYKILEESQEQQDRNEKDLLE (SEQ ID NO.: 1)
[0044] The present invention provides a peptide (Fusonex) with high-valence antiviral activity.
Fusonex has 36 amino acids and is derived from the C-terminal amino acid sequence
(No.117-151) of the ectodomain of HIV-1 (subtype E) trans-membrane glycoprotein gp41.
The polypeptide Fusonex in the present invention, even at very low concentration,
is capable of blocking the fusion process between viruses and cells, and between virus-infected
cells and uninfected ones. By blocking the entry, Fusonex is capable of preventing
the viruses from entry into cells, as well as containing the spreading of viruses
from infected cells to uninfected ones.
[0045] According to the virus-cell fusion assay, the fusion inhibition concentration for
Fusonex is 20-fold lower than that of T-20. Thus, the peptide of the present invention
has an improved efficacy in fighting against HIV infection, and should have a reduced
toxicity. Thanks to its high stability and high efficacy, the peptide of the present
invention is a much better inhibitor against virus fusion than T-20.
[0046] The antiviral activity of Fusonex includes preventing HIV from spreading to uninfected
CD4+ cells and other cells. In addition, the antiviral activity of the inhibitor of
the present invention does not require the elicitation of any immune response in the
host.
[0047] The inhibitor of the present invention can be applied to any biological fields related
to membrane fusion inhibition, including prevention of the transmittal of human or
non-human retrovirus (especially HIV) from uninfected cells. According to a preferred
embodiment of the present invention, the inhibitor Fusonex is used as inhibitor of
retrovirus (especially HIV) transmittal to uninfected human or non-human cells.
[0048] The inhibitor of the present invention can also regulate those biological processes
inside the cells that are related to the secondary structure of coiled protein helices.
As used herein, "Regulate" refers to an activating or a suppressing effect by the
peptide of the present invention on the level or the extent of a certain biological
activity inside the cells (compared to the situation in the absence of the peptide
in the present invention).
[0049] The present invention provides a novel fusion inhibitor, Fusonex. The present invention
also provides a joint administration of Fusonex with other agents, such as other antiviral
agents, in the treatment and /or prevention of viral infection, especially HIV infection.
These agents may or may not have the same sites or mechanisms in action as viral fusion
inhibitors. As a result, cooperative or synergistic effects may result from joint
drug administration.
[0050] According to an embodiment of the present invention, Fusonex can be administered
with other agents in all the following, including: simultaneous administration, sequential
administration, periodic administration, and periodic therapy (for example, administration
of an antiviral compound, then a second antiviral compound within a certain period
of time, repeating such administration sequence (namely the period) to reduce possible
drug resistance of the antiviral therapy).
[0051] The combination therapy of Fusonex with other antiviral agents provides a novel therapeutic
method that can reduce the effective dose and thus the toxicity of these antiviral
therapies. Furthermore, drug combination can inhibit viral infection of host cells
through different mechanisms, which not only increase the antiviral efficacy but also
prevent the viruses from building up tolerance against any therapy alone. The probability
of successful therapy is therefore increased.
[0052] The present invention also provides drug combination and preparations as therapies
or as preventives of virus (especially HIV) infection. This drug combination comprises
Fusonex in effective dose, at least one of other agents, and /or a pharmacologically
acceptable vector.
[0053] The agents used jointly with Fusonex include any drugs which are known or under experiment.
According to a preferred embodiment of the present invention. Fusonex are administered
together with another agent with a different mechanism. These agents include : antiviral
agents, such as the cytokines rIFNα, rIFNβ,.. and rIFNγ;.. r everse transcriptase
inhibitors, such as AZT, 3TC, ddI, ddC, Nevirapine, Atevirapine, Delavirdine, PMEA,
PMPA, Loviride, and other dideoxyribonucleosides or fluorodideoxyribonucleoside; viral
protease inhibitors, such as Saquinarir, Ritonavir, Indinavir, Nelfinavir, and VX-478;
hydroxyurea; viral mRNA capping inhibitors, such as viral ribovirin; amphotericin
B; ester bond binding molecule castanospermine with anti-HIV activity; glycoprotein
processing inhibitor; glycosidase inhibitors SC-48334 and MDL-28574; virus absorbent;
CD4 receptor blocker; chemokine co-receptor inhibitor; neutralizing antibody; integrase
inhibitors, and other fusion inhibitors.
[0054] Therefore, the present invention provides an improved antiviral therapeutics for
the treatment of broad viral (including HIV) infection. In addition, the present invention
provides a method of joint drug administration aimed at boosting the therapeutic effect,
including the use of Fusonex, at least a different medicine, and/or a pharmacologically
acceptable vector. The combination therapy can prevent the virus from building up
a tolerance against each therapeutic alone, and at the same time reduce drug toxicity
and enhance the therapeutic index.
[0055] As used herein, "viral infection" refers to a morbid state in which the virus invades
a cell. When the virus enters the healthy cell, it takes advantage of the host reproduction
mechanism to reproduce itself, then finally kills the cell. After budding from the
cell, those newly produced progeny viruses go on to infect other cells. Some viral
genes can also integrate into host chromosome DNA in the form of provirus, and it
is called as latent infection. The provirus reproduces itself with the replication
of the host chromosome, and can bring the infected people into morbidity at any moment
if activated by various factors inside and outside the body.
[0056] As used herein, "therapy or prevention of viral infection" refers to suppressing
the replication and the spread of viruses, preventing the virus self-settling inside
the host, and improving or alleviating the symptoms caused by viral infection. The
criteria for effective therapy include lower viral load, lower mortality rate, and/or
lower morbidity rate, etc.
[0057] As used herein, "therapeutics" refers to any molecule, compound, or drug conductive
to the treatment of viral infection or virus-caused diseases, especially antiviral
agents.
[0058] As used herein, "synergic action" refers to a joint drug administration that is more
effective than the additive action of merely using any of two or more therapeutics
to cure or to prevent viral infection. The synergic effect can increase the efficacy
of antiviral drugs and avoid or alleviate viral tolerance against any single medicine.
[0059] A peptide of the present application is defined as a complex of two or more amino
acids linked by peptide bonds. The peptide nomenclature is related to the number of
its constitutive amino acids. For example: a dipeptide contains two amino acid residues
while a tripeptide contains three, etc. A peptide composed of ten or less amino acids
is called an oligopeptide; while a peptide composed of more than ten amino acids is
called a polypeptide.
[0060] The description for the applications of Fusonex in the treatment of HIV and other
viral infection is as follows:
[0061] Fusonex is a polypeptide with antiviral activity. The peptides of the present invention
include Fusonex (a 36 amino acid peptide derived from gp41). These peptides also exist
in other envelop viruses. The peptides of the present invention are capable of suppressing
the spread of human and other mammal retroviruses, especially HIV.
[0062] It is believed that HIV and other viruses replicate themselves ceaselessly 24 hours
a day from the moment of infection. Thus, it is necessary to use antiviral agents
at different stages of viral infection. The present invention also provides a joint
administration of the peptide with different antiviral agents, to inhibit virus-cell
fusion and intercellular spread of viruses.
[0063] The description of a joint administration of drugs, including Fusonex, for the treatment
of HIV infection is as follows:
[0064] The acting target of Fusonex is on the glycoprotein gp41 of viral surface. The functional
mechanism of Fusonex is to inhibit fusion to prevent free virus granules from infecting
other cells, and to prevent the viruses from spreading from infected cells to other
cells.
[0065] It is believed that Fusonex, when administered jointly with one or more drugs with
different targets, may provide additive or synergic effects. The present invention
provides a joint administration of drugs, including Fusonex. Joint drug administration
can reduce not only the effective dose but also reduce the toxicity of the antiviral
drugs. In addition, it can improve the efficacy through a variety of mechanisms for
attacking the viruses. Finally, the joint administration of drugs can also prevent
or reduce the chances of the development of drug resistance.
[0066] The present invention provides therapeutics for HIV infection of human and other
mammals. This method comprises administering Fusonex in effective dose as well as
at least another agent that is preferably a different antiviral agent.
[0067] The present invention provides an improved method for the treatment of viral infection
(especially HIV infection). The present invention also provides a drug combination
for the treatment of HIV infection, the combination has Fusonex in effective dose
and at least a different antiviral compound. Preferably, Fusonex should be used together
with retrovirus inhibitors, viral protease inhibitors, cytokines, cytokine inhibitors,
or other viral fusion inhibitors. The joint drug administration will be more effective
in suppressing viral replication and transmittal.
[0068] The uses of the present invention include administration of Fusonex, and joint drug
administration of Fusonex with other antiviral agents. Fusonex and at least one of
other agents can be administered simultaneously (used as a mixture or separately),
or sequentially (including period therapy). The period therapy administers to the
patients an antiviral compound during a certain period and then administering a second
antiviral compound during another period. Such administration sequence (namely the
period) is repeated to alleviate the toxicity, as well as the drug resistance of the
therapy.
[0069] The present invention also provides a different period therapy that comprises administering
the peptide of the present invention first, and then another antiviral agent, and
then the peptide of the present invention again or another viral fusion inhibitor.
Consequently, the inhibitor of the present invention is administered together with
other antiviral agents.
[0070] The "joint administration" includes not only using two or more therapeutics together
as a mixture therapy, but also using two or more therapeutics separately but simultaneously,
for example, via different veins into the same body. The "joint administration" also
includes administering the drugs sequentially, namely administering one drug and then
the second drug.
[0071] The preferred antiviral agents used together with Fusonex can attack the viruses
in the following different modes: inhibiting the reverse transcriptase, inhibiting
the capping of viral mRNA, inhibiting HIV protease, inhibiting the glycosylation of
proteins, inhibiting integrase, and inhibiting viral fusion. Drugs based on those
attacking modes above include: antiviral agents, such as the cytokines, including
rIFNα, rIFNβ, and rIFNγ; cytokine inhibitors; reverse transcriptase inhibitors, such
as AZT, 3TC, ddI, ddC, d4T, Nevirapine, Atevirapine, Delavi Trdine, PMEA, PMPA, Loviride,
and other dideoxyribonucleoside or fluorodideoxyribonuceoside; viral protease inhibitors,
such as Saquinavir, Ritonavir, Indinavir, Nelfinavir, and VX-478; glycosidase inhibitors,
such as SC-48334 and MDL-28574; viral mRNA capping inhibitors such as ribovirin; amphotericin
B; ester bond binding molecule castanospermine with anti-HIV activity; hydroxyurea;
glycoprotein processing inhibitors; glycosidase inhibitors SC-48334 and MDL-28574;
virus absorbent; CD4 receptor blockers; chemokine co-receptor inhibitors; neutralizing
antibody; integrase inhibitors and other fusion inhibitors.
[0072] A description of the structure of the polypeptide Fusonex is as follows:
[0073] Fusonex peptide is a highly-effective fusion inhibitor capable of suppressing HIV
infection. Maybe this is because Fusonex can associate with gp41 on viral envelop
and interrupt the process of viral fusion. For example, in the course of the viral
protein gp41 transformation from natural structure into fusion structure, Fusonex
can compete for the binding site on viral gp41 and as a result, destroy the fusion
process between the viruses and the cells.
[0074] Fusonex, a peptide of the present invention, is derived from the amino acid residues
117-151 of HIV-1 trans-membrane protein gp41 and composed of 36 amino acids. Read
from the amino terminal to the carboxyl terminal, Fusonex has an amino acid sequence
as follows:
X-SWETWEREIENYTKQIYKILEESQEQQDRNEKDLLE-Z (SEQ ID NO.: 1)
[0075] "X" is an amino group or -X1-X2, wherein X1 is an imino group, and X2 is a hydrophobic
group, including carbobenzoxy, dansyl, tert-butyloxycarbonyl group, acetyl, and 9-fluorenylmethyloxycarbonyl
(FMOC), or a covalent-linked macromolecular vector group, including lipid-fatty acid
chelate, polyethylene glycol and carbohydrate.
[0076] Z is a carboxyl group or -Z1-Z2, wherein Z1 is a carbonyl group, and Z2 is an amino
group, tert-butyloxycarbonyl group, or a macromolecular vector group, including lipid-fatty
acid chelate, polyethylene glycol and carbohydrate.
[0077] According to an embodiment of the present invention, the amino acid substitutes have
protective properties. The protective amino acid substitutes comprise of amino acids
with similar charges, sizes, and/or hydrophobic characteristics to the amino acids
(one or more) they replace in Fusonex (SEQ ID NO.: 1) peptide sequence.
[0078] A description of the antiviral agents in joint administration with Fusonex is as
follows:
[0079] The fusion inhibitors of the present invention can be administered jointly with other
therapeutics in order to enhance its antiviral efficacy. According to a preferred
embodiment of the present invention, Fusonex is administered with other antiviral
agents, including drugs acting on different targets all through the virus replication
process, such as reverse transcriptase inhibitors, viral protease inhibitors and glycosylation
inhibitors, etc; antiviral agents acting on different targets all through the virus
spreading process; antiviral agents acting on different sites of the same molecule;
and antiviral agents capable of preventing or reducing the development of the drug
resistance. The working mechanisms as well as the benefits of joint administration
should be known to all scientific and technological personnel in the present field.
[0080] The inhibitors of the present invention can be administered jointly with retrovirus
inhibitors, including nucleoside derivatives. The nucleoside derivatives are improved
derivatives of purine nucleosides and pyrimidine nucleosides. Their acting mechanism
is to prevent RNA and DNA from being synthesized. The nucleoside derivatives, in the
absence of any 3'substituent that can be bound to other nucleosides, can suppress
the synthesis of cDNA catalyzed by reverse transcriptase and thereby terminate the
viral DNA replication. This is why they become anti-HIV therapeutic agents. For example,
AZT and ddT, both of them can suppress HIV-1 replication in vivo and in vitro, had
been approved as remedies for HIV infection and AIDS. However, use of these drugs
for treatment can lead to mass propagation of drug-fast HIV strains in addition to
many side effects.
[0081] The inhibitors of the present invention can be administered jointly with nucleoside
derivatives and non-nucleoside derivatives. The nucleoside derivatives include: 2',
3'-dideoxyadenosine (ddA); 2', 3'-diseoxyguanosine (ddG); 2', 3'-dideoxyinosine (ddI);
2', 3'-dideoxycytidine (ddC); 2', 3'-dideoxythymidine (ddT); 2', 3'-dideoxy-dideoxythymidine
(d4T) and 3'-azide2', 3'-dideoxycytidine (AZT). According to an embodiment of the
present invention, the nucleoside derivatives are halonucleoside, preferably 2', 3'-dideoxy-2'-fluoronuceotides,
including: 2', 3'- dideoxy -2'-fluoroadenosine; 2', 3'-dideoxy-2'-fluoroinosine; 2'3'-
dideoxy -2'-fluorothymidine: 2', 3'- dideoxy -2'-fluorocytidine; and 2', 3'-dideoxy-2',
3'-didehydro-2'-fluoronuceotides, including: 2', 3'- dideoxy -2', 3'-didehydro-2'fluorothymidine
(Fd4T). More preferably, the nucleoside derivatives are 2', 3'- dideoxy -2'- fluoronuceotides
wherein the fluorine bond is in the β conformation, including: 2', 3'- dideoxy -2'.
β - fluoroadenosine (F-ddA), 2', 3'-dideoxy-2'β-fluoroinosine (F-ddI), 2', 3'-dideoxy-2'β
-fluorocytidine (F-ddC). Joint drug administration can reduce the dosage of nucleoside
derivatives, and thereby reduce its toxicity as well as drug-resistance of the virus,
while maintaining their antiviral activity.
[0082] According to a preferred embodiment of the present invention, the combination of
antiviral peptides and nucleotide derivatives include Fusonex in effective dose, and
AZT, ddC, and/or d4T in effective dose for the treatment of HIV infection. A more
preferred drug combination includes: Fusonex and ddT in effective dose; and/or 3TC,
Viramune, Rescriptor, Sustiva, Loviride, Nevirapine, and Atevirdine in effective dose.
[0083] Fusonex can also be administered jointly with inhibitors of urdine phosphorylating
enzyme, including acyclouridine compounds, including benzylacyclouridine (BAU); benzoxybenzylacyclouridine
(BBAU); amethobenzylacyclouridine (AMBAU); amethobenzoxybenzylacyclouridine (AMB-BAU);
hydroxymethylbenzylacyclouridine (HMBAU); and hydroxymethylbenzoxybenzylacyclouridine
(HMBBAU).
[0084] Fusonex can also be administered jointly with cytokines or cytokine inhibitors, including:
rIFNα, rIFNβ, and rIFNγ; TNFα inhibitors, MNX-160, human r interferon αA, human r
interferon β, and human r interferon γ. A more preferred joint drug administration
includes Fusonex and β interferon in effective dose.
[0085] Protease inhibitors prevent the virus from maturing mainly during the viral assembly
period or after the assembly period (namely during the viral budding). Protease inhibitors
show an antiviral activity both in vivo and in vitro. After being administered protease
inhibitors, the AIDS patient HIV-level exhibits an exponential decline and their CD4
lymphocytes rise in number (
Decks, et al., 1997, JAMA 277:145-53). Joint administration of viral protease inhibitors with fusion inhibitor Fusonex
can produce a synergic effect and achieve satisfactory clinical results. The present
invention enables a method for treating HIV infection, which is a joint drug administration
using Fusonex in effective dose together with a protease inhibitor in effective dose,
the latter including: Indinavir, Invirase, Norvir, Viracept, and Agenerase.
[0086] Fusonex can also be used jointly with anti-HIV drugs that disturb 5'-mRNA processing,
such as virazole. The acting mechanism of virazole is unknown yet and presumed to
be competing with guanine in forming the mRNA capping structure, and/or disturbing
the methylation of these molecules. There is likely to be a synergic action between
Fusonex and virazole.
[0087] In addition, Fusonex can be administered jointly with amphotericin B. Amphotericin
B is a polyene antifungal antibiotic that can bind irreversibly with sterol. Amphotericin
B and its formate have an inhibiting effect against many lipid envelop viruses including
HIV Amphotericin B has a serious toxicity towards human body while its formate has
a much lower toxicity. Thus, Amphotericin B or its formate can be administered jointly
with Fusonex, and produce an anti-HIV synergic effect, which allows clinical doctors
to use Amphotericin B or its formate in lower doses without losing its antiviral activities.
[0088] Fusonex can also be administered jointly with the glycoprotein processing inhibitor
castanospermine, which is a vegetable alkaloid capable of inhibiting glycol protein
processing. HIV envelope contains two large glycoproteins gp120 and gp41. The glycosylation
of proteins plays an important role in the interactions between gp 120 and CD4. The
progeny virus synthesized in the presence of castanospermine has a weaker infectivity
than the parental virus. The joint administration of Fusonex with castanospermine
can produce a synergic effect.
[0089] The therapeutic effect of the joint administration of Fusonex with the above-mentioned
antiviral therapeutics can be evaluated by generally used methods in the present field.
For example, the joint effect of Fusonex and AZT can be tested through a variety of
in vitro experiments including: inhibiting HIV toxicity against cells, inhibiting
the formation of synplasm, inhibiting the activity of reverse transcriptase, or inhibiting
viral ability for RNA or protein synthesis, etc.
[0090] A description of the dosage formulations, dosage, and administration routes is as
follows. Drug combination is described first.
[0091] The drug combination of Fusonex with at least one of other therapeutic agents provided
by the present invention can be used for the treatment or prevention of human or non-human
viral infection. The joint drug administration provided by the present invention can
produce an additive/synergic effect.
[0092] The preferred drug combination contains Fusonex, and at least one of other antiviral
agents, such as reverse transcriptase inhibitors, protease inhibitors, mRNA processing
inhibitors, protein glycosylation inhibitors, virus adsorbent, CD4 receptor inhibitors,
chemokine co-receptor inhibitors, neutralizing antibody, integrase inhibitors, and
other fusion inhibitors, including nucleoside analogs or chain terminators; chemokine
co-receptor inhibitors AMD-3100 (
Tremblay, C. L. et al.,2000, J. AIDS 1:25(2)99-10)
[0093] According to an embodiment of the present invention, therapeutic agents that can
be used jointly with Fusonex include: 2-deoxy-D-glucose (2dGlc), deoxynojirimycinacycloguanosine,
virazole, rifadin, adamantanamine, rifabutine, ganciclover (DHPG), famciclove, buciclover
(DHBG), fluoroiodoaracytosine, iodoxuridine, trifluorothymidine, ara-A, ara-AMP, bromovinyldeoxyuridine,
BV-arau, 1-b-D-glycoarabinofuranoside-E-5-[2-bromovinyl]uracil, adamantethylamine,
hydroxyurea, phenylacetic heptanedione, diarylamidine, (S) - (ρ-nitrobenzyl) -6-thioinosine
and phosphonoformate. The present invention provides a drug combination of Fusonex
with any other above-mentioned compounds.
[0094] In addition, the peptides of the present invention can also be used as a preventive
measure for individuals who are exposed to HIV but have not been infected by it yet.
Examples of such a preventive measure include: the prevention of mother-baby transmittal
of the viruses; and the prevention of HIV infection in other situations, such as in
medical workers handling HIV-contaminated blood, blood products, and body fluid in
a medical accident. In these cases, the peptides of the present invention can be used
as a preventive vaccine. With the inoculation of the peptide of the present invention,
the host will produce antibodies that can inhibit HIV infection and neutralize HIV
viruses.
[0095] The present invention provides a preventive vaccination scheme, which comprises:
administering to the host the peptide at an effective concentration for eliciting
sufficient immune responses to neutralize the HIV, e.g., to develop the ability to
inhibit HIV infection of cells. The elicited immune responses can be detected by standard
techniques well-known to one of skill in the art. According to an embodiment of the
present invention, the peptide used as vaccine is administered by muscle injection.
[0096] In order to increase immune responses, the peptide of the present invention can be
administered with some proper adjuvants including: mineral gel, such as aluminium
hydroxide; surface active substance, such as lysolecithin; Puronic polyhydric alcohol,
polyanion; other peptides; oil emulsion agent; and other potential additives for human
use, such as Bacillus Calmette-Guérin (BCG) and small coryneform. The routes by which
the above-mentioned vaccine is administered include oral, intradermal, intramuscular,
intraperitoneal, intravenous, hypodermal, and mycteric routes.
[0097] A description of the dosage of Fusonex is as follows:
[0098] In the treatment of acute viral infection in mammals such as human, Fusonex should
be administered at an effective dose sufficient to suppress viral replication. This
effective dose can be determined by methods generally known to one of skill in the
art, including setting parameters such as biological half-life period, bioavailability
and toxicity, etc. As an example, Fusonex can be injected continually for 4-52 weeks
in a dose of 0.2-10.0 mg/kg a day. A preferred dose is 20mg~200mg a day. The most
preferred dose is 30mg——80mg a day; the duration is about 52 weeks.
[0099] The administration interval for Fusonex ranges from about 2 days to 1/4 days, most
preferably 1-1/2 days. When in the best dosage, Fusonex can attain a peak concentration
of 1mg/ml—10mg/ml in blood plasma. The blood concentration of Fusonex can be determined
as follows: make up a sterile injection of 20% Fusonex in some proper buffer saline
solution and inject it continually, then measure the blood concentration by HPLC.
[0100] The effective dose of the therapeutic agents such as the antiviral agents in joint
administration with Fusonex is determined on the basis of the recommended dosage of
various antiviral agents well-known to one skill in the art. The preferred dosage
for joint administration is about 10%-50% lower than the literature-recommended dosage
for separate administration. Medical professionals should pay attention to the dosage
at which toxic reactions begin to occur. When the functions of marrow, liver and/or
kidney are damaged, or serious drug interactions occur, the doctor should know how
and when to suspend or terminate the administration and to regulate the dosage to
a lower lever. In contrast, if the anticipated clinical therapeutic results are not
achieved, the doctor should also know how to enhance the dosage.
[0101] An effective therapeutic dosage refers to a dosage at which the drug combination
is sufficient to improve the patient's conditions or to prolong his survival period.
The toxicity and therapeutic effect of this type of drugs can be determined according
to standard pharmacological procedures of cell culture or animal experimentation.
For example, the procedures can be determination of the medium lethal dosage (LD
50, the dosage at which 50% of the experimental colony are killed) and the medium effective
dose (ED
50, the dosage at which 50% of the experimental colony are cured). The ratio of therapeutic
ability to toxicity is the therapeutic index and can be represented by LD
50 / ED
50. The higher the therapeutic index is, the better the compound is. Statistics obtained
in cell and animal experimentation can be used to infer the dosage range for human.
The dosage of this kind of compounds lies best within a certain hematic drug concentration
range, namely higher than ED
50 while with no or low toxicity, and then it can be regulated according to the dosage
formulation and administration route. Based on these data, the dosage for human use
can be determined accurately. The drug concentration in blood plasma can be measured
by HPLC.
[0102] A description of the dosage formulation and administration routes is as follows;
[0103] Patients are administrated directly with the drug combination containing Fusonex,
or with the mixture of the drug combination containing Fusonex with some proper carrier
or excipient in order to obtain the dosage for treating viral infection, especially
HIV infection. The preparation and administration technology for this application
is well-known to one of skill in the art.
[0104] The antiviral activity of the peptides of the present invention can exhibit a subtype
specificity, which means a specific peptide inhibits only a specific virus. The peptides
of the present invention are most sensitive to HIV-1, and such an advantage can be
utilized in this field of diagnosis reagent. For example, the anti-HIV-1 specificity
of this peptide can be used to identify the type of a certain isolated virus strain
(HIV-1 or HIV-2). For example, in the presence of the Fusonex peptide, an isolated
uninfected CD4+ cell is infected with an unknown virus strain, and then continuation
to culture the cell. Afterward, the retrovirus activity of cellular supernatant is
tested, and if the activity is totally suppressed, this virus strain should be HIV-1;
if the activity is not suppressed or suppressed only a little, the virus strain is
not likely HIV-1.
[0105] The present invention also includes the use of pharmacologically acceptable carrier
to prepare a proper dosage formulation for systematic administration based on the
peptides and/or drug combinations of the present invention. With appropriate carrier
and formulation, the peptides or the combinations of the present invention, especially
the combination prepared as a solution, can be administered by extragastrointestinal
routes including intravenous injection. The peptides or the combinations of the present
invention can also be prepared as a solution fit for oral administration by use of
a pharmacologically acceptable carrier well-known in the art. Appropriate carriers
are necessary for preparing the peptides or combinations into tablets, pills, capsules,
liquid, gel, syrups, slurry, suspensions, and other dosage formulations.
[0106] The peptides and drug combinations of the present invention can be administered by
routes well-known to one of skill in the art, including actinal, rectal, dialysis
membrane, or enteric administration; extragastrointestinal administration including
intramuscular, hypodermal, intramedullary, introthecal, directly intraventricular,
intravenous, intraperitoneal, intranasal, or intraocular injection; percutaneous,
local, vaginal administration, etc. The dosage formulations include tablets, pastille,
powders, suspensions, suppositories, solution, capsules, frost, plasters, and micro-motors.
For convenience, the drug combinations of the present invention can be made up by
routine methods into any pharmacologically acceptable formulation using one or more
physiologically acceptable carriers. The drug combinations of the present invention
can comprise one or more excipient and adjuvant to facilitate the processing of active
compounds. The formulation is determined by the administration route. To facilitate
the injection, the peptides or combinations of present invention can be prepared as
a solution, e.g., a physiological saline solution. In the case of dialysis membrane
administration, penetrants that facilitate the preparation penetration of barriers
should be used, and these penetrants should be generally known in this field.
[0107] The oral dosage formulation of the peptides and drug combinations of the present
invention can be ground together with solid excipients into a well-distributed mixture
and then processed into granules that are further processed into tablets or the kernel
of sugar-coated tablets; if necessary, proper adjuvant can be added to the mixture.
Proper excipients and fillers can be sugar, such as lactose, saccharose, mannitol,
or sorbicolan; fibrin products, such as cornstarch, wheaten starch, rice starch, potato
starch, glutin, tragacanth, methyl cellulose, hydroxypropylmethyl cellulose, sodium
carboxymethyl cellulose, and/or polyvinylpyrrolidone. If necessary, disintegrants,
such as cross-linked polyvinylpyrrolidone, agar, alginic acid, or its salt-like alginate
sodium. Proper coat should be provided to the kernel of sugar-coated tablets. The
coat can be made from concentrated sugar solution containing Arabic gum, talcum, polyvinylpyrrolidone,
carbopol gel, polyethylene glycol, titanium oxide, cellulose nitrate, and proper organic
solvent or solvent combination. Different combinations of coloring matter or edible
pigment can be added to the tablets or coat of sugar-coated tablets to discriminate
or designate the active compound.
[0108] The drug combination for oral administration includes the stuffing-type capsule and
the sealed soft capsule made of glutin and a plasticizer such as glycerin or sorbic
acid. The stuffing-type capsule contains a filler, such as lactose, an adhesive, such
as starch, and/or a lubricant, such as talcum or stearate. In addition, a stabilizer
can also be used to stabilize the active components. In the soft capsule, the active
compound can be dissolved or suspended in some proper liquid, such as fatty oil, liquid
olefin, or liquid-like polyethylene glycol. Besides, a stabilizer can also be added.
All the dosage formulations for oral administration should be convenient for patients.
In the case of actinal administration, the above mentioned combination can be prepared
into the convenient dosage formulations of troche.
[0109] In the case of inhalation administration, the peptides or combinations of the present
invention can be readily released in the form of aerosil by use of high-pressure package
or atomizer, or by use of some proper propellant such as dichlorodifluoromethane,
trichlorofluoromethane, dichlorotetrafluoroethane, carbon dioxide or other proper
gases. In the case of high-pressure aerosol, the dosage unit can be defined by the
quantity of measured release with one valve. The glutin capsule and cartridge used
as insufflator or exsufflator can be produced as a mixture containing the peptides
and a proper pulverous substrate (such as lactose or starch).
[0110] The peptides or combinations of the present invention can be prepared into a dosage
formulation for extragastrointestinal administration. For example, they can be prepared
into a formulation for injections that include cluster-drug injection or continuous
intravenous infusion. The preparation for injection use can be packed in the form
of unit dosage. For example, it can be packed into ampoules. Preparations in large
dosage can also be packed in the form of unit dosage, such as ampoule or large-dosage
container, and added with preservative. The combinations of the present invention
can take the form of suspension, solution or emulsion with oil or water as its medium,
and can contain some additives, such as a suspending agent, stabilizer, and/ or dispersant.
[0111] The drug combinations for extragastrointestinal administration can be in a water
solution of the active substance, namely the water-dissolved form. The suspension
of the active substance can also be produced as a proper oil-like suspension injection.
The proper oleophilic solvent or vector includes fatty oil such as gingeli oil, or
synthesized fatty acid ester such as ethyl oleate or triglyceride, or liposome. Water-like
suspension for injection can contain substance that increases the suspension viscosity,
such as sodium carboxymethyl cellulose, sorbic alcohol, and glucosan. The above mentioned
suspension can also contain selectively a proper stabilizer or substance that increases
the compound solubility in order to prepare a high-concentration solution. The active
component of the pulverous injection can be dissolved in some proper solvent, such
as sterile water for injection that is in the absence of pyretogen, before administration.
[0112] The peptides or combinations of the present invention can also be prepared into rectal
dosage formulations such as suppositories or retained enemas. They can be prepared
with frequent substrate such as cacao butter or other glyceryl esters.
[0113] Apart from the dosage formulations that have been described, the peptides or drug
combinations can also be prepared as long-acting dosage formulations that can be administered
by hypodermal or intramuscular planting or intramuscular injection. Therefore, the
peptides and its derivatives or drug combinations can be prepared with proper polymers,
hydrophobes (oil emulsion, for example), ion exchange chromatography, or hardly soluble
derivatives, such as hardly soluble salt.
[0114] The drug carriers for hydrophobic peptides or combinations of the present invention
are a co-dissolved system of organic polymers and aqueous phase that blends with water
and contains benzyl alcohol and non-polar surfactant. This co-dissolved system can
be a VPD co-dissolved system. VPD is a solution containing 3% (W/V) benzyl alcohol,
8% (W/V) non-polar surfactant multiethoxyaether and 65% (W/V) polyethylene glycol
300 in absolute alcohol, while a VPD co-dissolved system (VPD: 5W) is prepared with
VPD diluted in water by 1:1 and 5% glucose. This kind of co-dissolved system can dissolve
hydrophobes better while it will produce low toxicity in systemic administration.
As long as its solubility and toxicity are not changed, the proportions of the co-dissolved
system can be altered greatly. In addition, the components of the co-dissolved carrier
can also be changed. For example, other non-polar surfactant with low toxicity can
be used to substitute for multi-ethoxyaether; the proportion of polyethylene glycol
can also be changed; other biologically-blending polymers, such as polyvinylpyrrolidone,
can be used to substitute for polyethylene, other sugar or polyose can be used to
substitute for glucose.
[0115] The drug combinations can also include proper carrier-like excipients in solid or
gel phase. These carriers or excipients include calcium carbonate, calcium phosphate,
various sugar, starch, cellulose derivatives, gelatin, or polymers, such as polyethylene
glycol. The drug combinations of the present invention also include the combination
of active components in effective dose used to obtain the therapeutic purpose. The
method of determining effective dose is well-known to one of skill in the art.
[0116] A description for the uses of peptides of the present invention is as follows:
[0117] The Fusonex peptide (SEQ ID NO.: 1) shows an effective antiviral activity. As a result,
the peptide and its derivatives can be used as human and non-human retrovirus inhibitors,
especially, HIV inhibitors, and thus preventing the virus from spreading to uninfected
cells.
[0118] The peptides of the present invention can be used to suppress the spread of human
retroviruses, including HIV-1 and HIV-2 strains and human T-lymphocytes (HTLV-I and
HTLV-II). The peptides of the present invention can also be used to suppress the spread
of non-human retroviruses, including Boving leucosis virus, feline sarcoma virus,
leucovirus, simian immunodeficiency, leucosis virus, leucovirus, and ovine progressive
pneumonia virus.
[0119] The peptides of the present invention are also likely to suppress the spread of other
retroviruses and/or non-retroviruses, including human respiratory syncytial virus,
distemper virus, Newcastle disease virus, human parainfluenza virus and influenza
virus.
[0120] Furthermore, the present invention also provides the use of the peptides in joint
drug administration for the treatment of diseases caused by the above-mentioned retroviruses
and non-retroviruses.
[0121] A description for the uses of joint administration for suppressing HIV is as follows:
[0122] The present invention provides joint administrations of Fusonex and other therapeutic
agents. The joint drug administration can prevent synplasm formation and HIV replication,
and thus suppressing the reproduction of HIV in the patients. The joint administrations
of the present invention can also be used to alleviate or cure the diseases associated
with HIV infection. For example, antiviral peptide Fusonex can be administered jointly
with antifunal agents, antibiotics, or other antiviral agents to suppress HBV, EBV,
CMV infection and other accidental infection (including TB).
[0123] The best use for Fusonex is to suppress HIV infection. The effective dose for joint
administration can be based on the methods as follows. For example, to prepare the
drug in a proper carrier and to administer it by any proper routes, including: injection
(such as intravenous, intraperitoneal, intramuscular, and hypodermal injection, etc.);
epithelium or mucosa absorption, such as actinal mucosa, rectal, vaginal epithelium,
pharynx nasalis mucosa, enteric mucosa, etc; per os; transdermal or other pharmacologically
feasible administration routes.
[0124] Compared with existing drugs in the art, the peptides of the present invention has
the following advantages: a remarkably improved efficacy for suppressing HIV membrane
fusion, a better stability and a higher valence; while the efficacy is improved, the
dosage can be reduced and therefore the side effects are reduced.
Examples
[0125] Examples to illustrate the present invention are as follows:
Example 1: production and purification of Fusonex.
[0126] Fusonex was synthesized on the 431 A-typed biosystem polypeptide synthesizer. The
Fast-Moc chemical method was used in this synthesis, and standard solid- phase synthesizing
technique was used with amino acids protected with 9-fluorenylmethyloxycarbonyl (FMOC).
The reagents include TFA, water, 5% anisyl sulfide, 2.5% ethylene disulfhydrate, and
0.8M crystalline phenylphenol.
[0127] In order to prolong the biological half-life of Fusonex, its amino terminal was acetylated,
and carboxyl terminal was amidated. The peptide was automatically dissociated from
the resin on the apparatus, and the side chain bulky groups were automatically removed.
Dissociated from the resin, the crude Fusonex peptide was precipitated for 20 minutes
in cold ether at four-fold volume. After the centrifugation, the peptide was washed
two times in cold ether and then dried for 24 hours.
[0128] The crude Fusonex peptide was purified by HPLC. On the C18 column (15 µm global filler),
linear elution was carried out in water/acetonitrile containing 0.1% TFA. The purity
of the purified Fusonex peptide, which was measured by analytical HPLC, was higher
than 95%. At last, Fusonex is verified by amino acid sequencing and electron jet mass-spectra.
The molecular weight of purified Fusonex was 4641.24D.
Example 2: an elution experiment of Fusonex
[0129] The method used in Fusonex elution experiment is as follows:
[0130] On Superdex 75 chromatography column, the excess Fusonex and the complex of Fusonex
and gp41 N-peptide (35-70) was eluted. The eluent was phosphate buffer. The total
collection volume for the curve was 30ml. According to the results, an elution profile
(Figure 2) was drawn, which has shown that the elution peak of the complex of Fusonex
and gp41 N-peptide (35-70) was at the position of 13.2ml, and that of Fusonex itself
was at the position of 17.3ml
Example 3: determination of the structure of Fusonex complexed with gp41 N-peptide
[0131] Circular dichroism spectra were used to determine the structure of Fusonex complexed
with gp41 N-peptide. First, the sample was diluted to 25 µM, pH 7.4 in 0.1M NaCl/20mM
kalium phosphate, and then the secondary structure of Fusonex complexed with gp41
N-peptide was determined by CD spectra. The analysis was carried out on Aviv 62A DS
circular dichroism spectrum apparatus. The peptide solution containing Fusonex and
gp41 N-peptide (35-70) was measured in a wavelength range of 200—260nm.
[0132] The conditions for the circular dichroism spectra were: 20°C, the breath of circularly
polarized light was 1.5 nm, and the step was 0.5 nm, the time constant was 2.0 seconds,
and the length of light cell was 10 mm. Three-level polynomial was used for the correction
with the blank data. The temperature of sample was maintained with thermoelectric
holder and its error range was within 1°C.
[0133] The results were shown in the circular dichroism (CD) spectra (Figure 3). According
to Figure 3, it has been shown that the complex of Fusonex and gp41 N-peptide (35-70)
had a secondary structure of 100% α -helices. Degree (θ) was used as the unit of the
ellipticity of the spectrum y-axis, its ellipticity θ was about -40, 000/deg cm
2 dmol
-1 (Figure 3) at 222 nm.
Example 4: testing the stability of Fusonex and T-20
[0134] This experiment determined the stability of a polypeptide by measuring its melting
curve at different temperatures. The experiment was carried out on Aviv 62A DS circular
dichroism spectrum apparatus. The temperature range for heating peptide solution was
from 20°C to 95 °C
[0135] This experiment tested the stability of a polypeptide based on to its melting curve
at different temperatures. The 50% melting temperature for Fusonex complexed with
gp41 N-peptide (the curve on the right side, represented by solid circles) is 70 °C,
while the 50% melting temperature for T-20 complexed with gp41 N-peptide (the curve
on the left side, represented by open circles) is 51°C. When other conditions were
the same, Fusonex complex needs a higher temperature to melt.
[0136] The results were shown in the melting curve (Figure 4) of Fusonex complex and T-20
complex. According to Figure 4, it has been shown that the stability of Fusonex was
higher than that of T-20.
Example 5: the inhibitory activity of Fusonex against HIV-1 infection
[0137] In this implementing example, it has been shown in the cell-cell fusion assay that
Fusonex can block viral infection very effectively. In the fusion assay under the
same conditions, the IC
50 of Fusonex was 1.2±0.2 nM, while the IC
50 of T-20 was 23±6 nM. The 50% inhibiting concentration (IC
50) of Fusonex was about 20 times lower than that of T-20. It has be shown by its high
valence that Fusonex was more effective in preventing HIV viruses from fusing with
human cells, as well as inhibiting HIV-induced intracellular fusion, thus blocking
the virus invasion into uninfected cells.
[0138] The detailed description of the assay is as follows:
[0139] The antiviral activity of Fusonex can be determined by
in vitro testing. In the present invention, a luciferase experiment was used to quantificationally
test the ability of Fusonex to inhibit the formation of synplasm induced by HIV-1
gp160
HXB.
[0140] The specific experiment methods are as follows: The T7 promoter was inserted into
the pSP64 upstream sequence of the cloning site to assemble a luciferase reporter
gene plasmid―Pst7luc. The internal ribozyme entry site (IRES) of encephalomyocarditis
virus (CMCV) was linked with the 5'-terminal of luciferase gene as well as the downstream
area of T7 promoter. CD4 gene, T7 polymerase gene, and HIV-1 gp160
HXBgene were subcloned into the mammalian expression plasmid—PMT3.
[0141] In a 10cm culture dish, the 293T cells were transferred by Calcium Phosphate Method.
Equal quantities of gp160
HXB gene and T7 polymerase gene were used to transfect the effector cells, and pSP64
and CD4 gene were used to transfect the target cells. The PMT3 plasmid in the absence
of gp 160
HXB or CD4 gene was set as a negative control.
[0142] The cells with non-serous DMEM were rinsed, after the DNA precipitate was added.
The cells were cultured for 30-40 minutes at 37 °C in 9ml/dish non-serous DMEM. Afterwards,
the cells were stirred up and down gently in the dish by pumping with a transfer pipette,
and then the cells precipitated after centrifugation were collected. Cells in each
dish were resuspended in 3m1~4 ml DMEM containing 10% FBS, and then the effector cells
were mixed with target cells (45 µl each) in 96-well culture plate so as to achieve
a well-distributed state.
[0143] First, Fusonex or T-20 was dissolved in DMSO, and then diluted by 20-fold. The solution
as a stock solution was put to serial dilution in culture medium before use. In each
well, 10 µl culture medium or PBS was added, or Fusonex or T-20 diluent was added
at concentrations augmenting continuously from zero. The mixture of target cells,
effector cells, and the fusion inhibitor were stirred, and then cultured at 37°C for
8 hours. Before analyzing the luciferase gene, first the culture media were blotted
in wells and then the cells were dissolved in 60 µl cytolytic buffer at a 1:1 concentration.
40 µl lysate was transferred to each well of the black 96-well culture plate and then
100µl fluorescein and coenzyme A were added. Three samples for each concentration
point were repeated. Two minutes after adding luciferase substrate to the black 96-well
culture plate, measure the chemical fluorescence intensity with Spex fluorolog-3 fluorimeter,
the emission wavelength being 552 nm and slit breadth being 7mm. The average and standard
deviation were calculated from the three data of each concentration point.
[0144] The inhibition data in the experiment was fitted with the simple affinity balance
formula (% luciferase activity = 100/(1+(C/ IC
50)) and then reckoned up the IC
50 value. The results were shown in the inhibition profiles of Fusonex and T-20 against
viral fusion (Figure 5). Figure 5 indicated that the 50% inhibition concentration
(IC
50) of Fusonex (circles) was about 1/20 of that of T-20 (squares). The IC
50 value was 1.2±0.2 nM for Fusonex, while it is 23 ± 6 nM for T-20. In other words,
the valence for Fusonex fusion inhibition was 20 times higher than that of T-20.
[0145] In conclusion, Fusonex is a compound capped at both terminals and composed of 36
amino acids in a specific sequence. This inhibitor and its combination have a strong
inhibitory activity against HIV infection, as well as with better stability and higher
valence. Therefore, it can improve therapeutic efficacy while requires a lower dose,
which could reduce the side effects.
SEQUENCE LISTING
[0146]
<110> Zhou, Genfa
<120> A PHARMACEUTICAL USED FOR TREATING HIV INFECTION, THE COMPOSITION AND USES THEREOF
<130>
<160> 2
<170> PatentIn version 3.1
<210> 1
<211> 36
<212> PRT
<213> Artificial
<220>
<223> a peptide derived from HIV trans-membrane glycoprotein gp41
<400> 1

<210> 2
<211> 35
<212> PRT
<213> Human immunodeficiency virus type
<400> 2


SEQUENCE LISTING
[0147]
<110> Zhou, Genfa
<120> A PHARMACEUTICAL USED FOR TREATING HIV INFECTION, THE COMPOSITION AND USES THEREOF
<130>
<160> 2
<170> PatentIn version 3.1
<210> 1
<211> 36
<212> PRT
<213> Artificial
<220>
<223> a peptide derived from HIV trans-membrane glycoprotein gp41
<400> 1

<210> 2
<211> 35
<212> PRT
<213> Human immunodeficiency virus type 1
<400> 2

